Meruru endings:Correct me if Im wrong, but wasn't there an ending in Meruru wherein that exactly happened? Albeit, Rorona returned to her old pre-Totori self. Or is this different?
There wasn't, no. The only endings where Rorona isn't a child are the 'Just as planned' end where she ends up 14 forever without any of her memories (she doesn't even know who Totori is), and the Tea Party end where all the girls end up 14 forever and... well I'm not usually one to call things like this creepy but that ending really is disturbing to watch. So basically in both of those she's aged up a bit but considering she was older than 14 by the end of Totori as it is, I don't think you can really argue either of those have her restored to her 'original' form.
Also, one of the screenshots of the added events they released has Meruru wondering if the potion of youth she made is reeeally going to return Rorona to normal, and another one has Astrid reacting to Meruru trying to lecture her about something (no screenshot of what Meruru said to her) by challenging her to make a more complete one. So yeah, it seems to be suggesting she finds out about Astrid's obsession with 14 year olds and decides to take it upon herself to make a proper one to give us the end we want.
Also, one of the screenshots of the added events they released has Meruru wondering if the potion of youth she made is reeeally going to return Rorona to normal, and another one has Astrid reacting to Meruru trying to lecture her about something (no screenshot of what Meruru said to her) by challenging her to make a more complete one. So yeah, it seems to be suggesting she finds out about Astrid's obsession with 14 year olds and decides to take it upon herself to make a proper one to give us the end we want.